the best bet for backgrounds with plecos is to use epoxy coats over it 5 or more layers, and dust the last coat with fine sand to take away any shine from the epoxy, it protects your background for many years from the plecos rasping on it, bnps aren't as bad as large common plecos or royal plecos, the royal plecos actually teeth and will tear into anything with no problems, but BNs don't they just have rasping pads and in general are fairly gentle on most things.

in regards to securing styrofoam backgrounds to the back of the tank could you fashion in tank magnets into the back of the design preferably into your rocks? do you think magnets will hold it down enough? - im curious as to how dirty under these things get if theres any gaps from setup or later on in between the background and the glass have you had any problems at all?

Awesome work though mate i really like the way it comes out with your tank looks awesome!

So I'm kind of resurrecting old threads to see how an idea has held up for use in my next project!

this background looks fantastic, great job. I wasn't sold on DIY backgrounds, concrete and quikcrete weren't appealing due to the ph going wacky and the potential for crumbling. styrofoam always looked like styrofoam to me but this definitely is passable for rock

since it's a planted tank I'm guessing the bottom inch or 2 of the background is buried in substrate, any signs of decomp on the styrofoam or wearing through the drylok? If you wanted to clean the algae off would wiping it with a cloth be enough or would it take to much scrubbing and risking removal of the drylok?

i watched joey's foam factory video, are those the style of tool you used here? Impressive details for a knife so was curious on the tools needed

Sorry for the delay ... I found frequenting this site was bad for my budget! Always wanting to do new projects, its too easy to spend money. I also ran out of energy and have cut down to 3 tanks. This one is still running, though I am preparing for a rescape.

I haven't seen any issues with the background degrading, either naturally or from the bristlenose pleco in there. I've never really tried to remove algae, there isn't much of it. In other words, its held up perfectly thus far.

One mistake I made, and this is really only applicable for the planted tank, is making the bottom of the background wider to create the caves (its 2 inches wide at the top, and 4 inches wide on some of the bottom. The problem is I want my plants to grow against the background, but I can't plant them as far back as I need to.

I haven't seen Joey's video, but there are lots of ways to cut the foam. I used a dremel tool to get the initial depth. Take your time, I rushed mine and wish i had put more detail into it, though with the plants growing it works really well.

Three month update. Everything holding up pretty well. Starting to get a bit of brown algae growing on the background, mostly because I switched to live plants and have been running stronger lighting longer. I don't mind it though as it feels a bit more natural to me.